A variety of facilities employ context providing systems. Context providing systems are systems that include or have access to information that about the operation of the facility or its occupants. Healthcare facilities often include one or more context providing systems examples of which include, electronic record management systems, registration systems, and scheduling systems. These facilities can be quite large and require a substantial amount of energy or other resources when in operation. However, at any given time, only a portion of these facilities may be in use. This can result in substantial waste of energy and other resources.
One illustrative facility is a hospital having a surgical suite. Surgical suites have unique requirements for effective ventilation. For example, anesthetic gas and vapors that leak out into the surrounding room during medical and surgical procedures are considered waste anesthetic gases. They include nitrous oxide and halogenated agents (vapors) such as enflurane, isoflurane, sevoflurane, desflurane, and halothane. Potential adverse health effects of exposure to waste anesthetic gases include loss of consciousness, nausea, dizziness, headaches, fatigue, irritability, drowsiness, problems with coordination and judgment, as well as sterility, miscarriages, birth defects, cancer, and liver and kidney disease. Additionally, airborne contaminants such as microorganisms may contribute to post-operative infections in patients. These contaminants can most effectively be removed with adequate circulation that includes exchanges of the air in the operating room with clean filtered air.
To deal with the unique challenges of the surgical suite, the American Institute of Architects (AIA) suggests an air exchange rate of 15 air changes, with three outside air changes every hour. American Society of Heating, Refrigeration and Air Conditioning Engineers (ASHRAE) recommends 20-25 air changes per hour with 4-5 outside air changes per hour. It is common for systems to be designed to ASHRAE recommendations. Maintaining such high air exchange rates requires significantly more energy for a heating, ventilation, and air conditioning (HVAC) system than more typical HVAC applications. This makes operation of an HVAC system much more expensive for a surgical suite than it is for a comparable volume of commercial office space or other space.
One reason that specific environmental conditions are recommended is to reduce the risks associated with surgical site infections. In 2009, it was reported by the CDC that surgical site infections were the second most frequently reported nosocomial infection accounting for 22% (approximately 500,000 SSIs out of 27 million surgical procedures performed annually) of the 1.7 million nosocomial infections each year. Of the 1.7 million patients with nosocomial infections, 99,000 deaths resulted among hospitalized patients in the United States. For patients with surgical site infections that die, 77% of those patients' cause of death is from the surgical site infection. Depending on the location of the surgical site infection, it is estimated that healthcare costs can increase to upwards of $20-50,000, resulting in $1-10 billion dollars in healthcare costs for surgical site infections alone per year in the United States. Patients with surgical site infections had their hospital length of stay increase by 7.3 days.
Although it is not specifically known whether or not substandard operating room ventilation has a direct effect on the development of a surgical site infection without performing baseline testing on the care environment specifically, it would be to the advantage of the clinical personnel to be made aware of substandard air ventilation and support of the patient care environment so they can address any issues that may contribute to the decrease of patient safety where hospital acquired infections or more specifically perioperative surgical site infections are concerned. If it is possible to reduce surgical site infections with early notification of poor patient care environment air quality, naturally, not only would this affect contribute to a decreased length of stay and subsequent reduction in dollars spent on patient care to treat the surgical site infection, but also a more optimum patient experience.
Existing systems can provide for both an “occupied” mode and a “setback” mode for an HVAC system in use with an operating room. Typically such systems require direct intervention such as a manual input by a user. These systems allow for the case where a user may neglect to change the HVAC control mode for an operating room to occupied in advance of a surgical procedure. This results in wasted time as a room is brought to the correct operating conditions. Also, a user may neglect to setback the system after a surgical procedure is complete. This results in the operating room being maintained in an “occupied” mode for prolonged periods of time and accruing unnecessary utility costs associated with conditioning changing the air. Continuous communication between facility staff and clinical staff is not feasible in order to optimally set setback time schedule. For this reason, the use of time schedules are abandoned or set extremely conservatively. Another option that has been implemented is the use of occupancy sensors. These have had very limited effectiveness due to the frequency that staff enters the room at times other than for a surgical procedure. Such times are for cleaning, stocking supplies, moving equipment, and preparation.
Accordingly, there is a need for a method to allow automated control and monitoring of building systems based on inputs from a context providing system. There is also a need for a system and method that will reduce the total cost of HVAC operation for surgical suites. There is a further need for an HVAC and building control system that can automatically adjust the operating mode of a room based upon the actual use of the space.